In the mobile electronic device such as the mobile phone device, or the like, the direction operation key used to execute a selection of menu items displayed on the display portion, etc., for example, is provided. Also, the direction operation key is used to execute the operation in response to the contents displayed on the display portion, for example, to change an area of a map displayed when the user executes a map search. The key in which the switch is arranged in four directions on the upper/lower and right/left sides respectively is most popular as such direction operation key. In addition, various types of keys such as the roller type used to select, scroll, or the like the display contents by turning the key, the stick type, and the like are known (see Patent Literature 1).
The display contents on the display portion are displayed by arranging the icons indicating respective menu items in four directions on the upper/lower and right/left sides in response to the operable directions of the direction operation key or moving (scrolling) the screen display longitudinally and laterally, for example. Also, the direction operation key is easy to operate because this key is provided in the position in which such key can be operated with the thumb of one hand.
As the mobile electronic device such as the cellular phone, or the like, the device equipped with the operation portion to which various keys for inputting the information are provided and the display portion for displaying various input information in answer to the key operation of this operation portion is known.
Also, as the display portion, the display constructed to select the desired item among various menu items, and the like in answer to the key operation of the operation portion and display the selected item is known. Meanwhile, as the operation portion to which such key operation is applied, for example, the device constructed to have the direction operation key used to select the menu items, the decision button used to define the selected content, and the like (this device is referred to as an “input device” hereinafter) is also known.
The direction operation key in such input device is used to execute the operation in response to the contents displayed on the display portion, for example, to move/change an area on a map displayed when the map is searched, or the like. Also, as such direction operation key, the key in which four switches are arranged equiangularly in four directions on the upper/lower and right/left sides respectively is popular. In addition, the keys having various shapes and configurations such as the roller type used to select or scroll the display contents displayed on the display portion by executing a turning operation in the circumferential direction, the stick type, and the like are known.
In contrast, as the decision button, the button arranged in the center portion of the direction operation key, the button arranged in a separate position different from the direction operation key, and the like are known (see Patent Literature 2, for example).
By the way, as the method of displaying various information on the display portion, for example, the method of arranging the icons indicating respective menu items in four directions on the upper/lower and right/left sides to correspond to the operation positions of the direction operation key, the method of moving (scrolling) the screen display longitudinally and laterally to display the information, and the like are known. Also, since the direction operation key is provided in a predetermined position such that it can be operated with the thumb of one hand, such key is easy to operate.
(Patent Literature 1) JP-A-11-194872
(Patent Literature 2) JP-A-2001-331253 (FIG. 2, FIG. 6)